Postmenopausal Squamous Atypia: Cytologic Features, Hybrid Capture 2 Tests and Contribution to the ASCUS Pool

Postmenopausal squamous atypia (PSA) mimics squamous intraepithelial lesion (SIL). We investigate the PSA contribution to the atypical squamous cells of undetermined significance (ASCUS) pool, its cytologic features and Hybrid Capture 2 (HC2) relative light unit/cutoff (RLU/CO) values.

658 ASCUS Pap tests in women ≥55 years were reviewed to select those with koilocyte-like cells and/or atypical parakeratosis. Follow-up was positive when a biopsy showed SIL or carcinoma or a later HC2 test was positive.

Sixty-nine cases (10.5%) were selected. Forty-two (60.9%) were HC2 negative, and 27 (39.1%) were HC2 positive. Follow-up was available for 23 (54.7%) HC2-negative and 19 (70.3%) HC2-positive cases. No HC2-negative (0%) and 8 HC2-positive (42.1%) cases were positive on follow-up. Within cases negative on follow-up, 3 were PSA on biopsy. PSA was characterized by perinuclear halos, mild nuclear enlargement, smooth nuclear contours, and smooth chromatin. PSA-associated RLU/CO values were 0.25-2.95. Cases with SIL or carcinoma had RLU/CO values from 3.78 to 1,241.59.

PSA contributes 0.5-2.3% to the ASCUS pool in women ≥55 years old. HC2 testing with RLU/CO of ≥1 may result in PSA occasionally testing positive. A different cutoff is not recommended but awareness of this caveat is important.